Tear out mesh writers

Totally unused in Minetest

include/ISceneManager.h

@@ -13,7 +13,6 @@
 #include "dimension2d.h"
 #include "SColor.h"
 #include "ESceneNodeTypes.h"
-#include "EMeshWriterEnums.h"
 #include "SceneParameters.h"
 #include "ISkinnedMesh.h"
 
@@ -109,7 +108,6 @@ namespace scene
 	class IMeshLoader;
 	class IMeshManipulator;
 	class IMeshSceneNode;
-	class IMeshWriter;
 	class ISceneNode;
 	class ISceneNodeFactory;
 
@@ -433,10 +431,6 @@ namespace scene
 		See IReferenceCounted::drop() for more information. */
 		virtual ISceneManager* createNewSceneManager(bool cloneContent=false) = 0;
 
-		//! Get a mesh writer implementation if available
-		/** Note: You need to drop() the pointer after use again, see IReferenceCounted::drop()
-		for details. */
-		virtual IMeshWriter* createMeshWriter(EMESH_WRITER_TYPE type) = 0;
 
 		//! Get a skinned mesh, which is not available as header-only code
 		/** Note: You need to drop() the pointer after use again, see IReferenceCounted::drop()